there were several examples across many of the later books where Ankh-Morpork was changing, evolving and "modernising".. and the Discworld with it..
without going into spoilers, I think it's fair to say that a number of technological advancements (discworld flavoured of course) bring an element of steampunkery to the general atmosphere, which is in turn a fertile environment for Pratchett's satire on roundworld.